1. Technical Field
The invention is related to the fabrication of vehicles such as spacecraft having on board extremely sensitive magnetometer experiments for sensing distant magnetic fields whose measurements are susceptible of being distorted by local magnetic fields of components comprised within the spacecraft. More specifically, the invention is concerned with ways of fabricating such spacecraft in such a way as to at least nearly eliminate such local magnetic fields of the individual components on board the craft.
2. Background Art
Measuring distant magnetic fields in an exploratory vehicle such as a spacecraft or satellite requires a sensitive magnetometer on board the craft. The problem is that a magnetometer sufficiently sensitive to measure distant magnetic fields (of other planets comets or asteroids, for example) is sensitive to local magnetic fields as well. Various components aboard the spacecraft (such as communication equipment, on-board experimental apparatus, guidance and navigation hardware and the like) can have current-generated magnetic moments, serving as local magnetic field sources. Such local field sources distort the measurements of distant magnetic fields by the magnetometer.
One solution has been to estimate the various local fields surrounding the magnetometer and compensate for them in processing the measurement data generated by the magnetometer. However, such a solution is fraught with uncertainties, not the least of which is the uncertainty involved in measuring or estimating the local magnetic field produced by a given component aboard the spacecraft. It would be much more desireable to measure distant magnetic fields with the magnetometer in the absence of local magnetic fields, thereby avoiding the necessity of having to "back-out" their distortions in the magnetometer data. However, this has not seemed possible because the components required to control a spacecraft necessarily have their own magnetic moments.
Accordingly, it is an object of the invention to provide a way of quickly and accurately measuring the magnetic field of each individual component to be placed in the spacecraft.
It is a further object of the invention to provide a way of nullifying the magnetic field of each component so that, when placed on the spacecraft, it will not disturb the on-board magnetometer.
It is another object of the invention to provide a way of quickly measuring the magnetic field in three dimensions of each component to be placed on a spacecraft, permanently nullifying the component's magnetic field and then re-measuring the component's magnetic field to confirm that it has been effectively nullified.
It is a still further object of the invention to assemble a spacecraft almost entirely of individual components whose magnetic fields have been thus measured and permanently nullified.